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HERE'S HOW- Choose the Proper Extension Cord PDF Print E-mail
Written by PAT LOGAN, Creators Syndicate   
Thursday, 03 March 2011 02:46

Dear Pat: I plan to try some power-tool projects myself. I was looking for extension cords at the home center, but I don't know what to buy. How do I determine what type to get? — Marcia H.

Dear Marcia: An extension cord seems like a pretty simple, straightforward item to purchase at first glance. It actually is quite an important purchase for safety and getting the maximum performance from your power tools.

An extension cord is definitely not one of those items where you look for the cheapest one on sale.

Always buy a three-prong grounded extension cord even if most of your power tools have only a two-prong plug. Those tools will work fine with the threeprong extension cord, and you never know when you may use a power tool with a three-prong plug. Never force a three-prone power tool cord into a two-prong extension cord. It can be hazardous if the tool shorts out.

There are extension cords rated for indoor use and outdoor use.

The ones rated for outdoor use have tougher insulation and are designed to be stronger overall. Any outdoor-rated cord can safely be used indoors, too. Most flat extension cords are only rated for indoor use because the outer plastic covering functions as both the insulation and the protective jacket.

Outdoor cords have wire insulation plus an extra jacket.

The thickness of the copper wires inside extension cords varies. You have to make sure the extension cord has large enough copper wire to handle the electrical power your tools require.

Power tools can draw from as little as 2 amperes of current to as high as 15 amperes. A largerdiameter piece of copper wire can carry more electrical current.

All extension cords will be marked with the copper wire gauge. A lower gauge number indicates a larger wire. Check the nameplates on the power tools you have for the amperes of current or wattage they draw.

Purchase an extension cord with the appropriate wire gauge to handle the most powerful (highest amperes or wattage) tool.

Using an extension cord with larger wire than a small power tool needs is not a problem.

Here are some general guidelines to follow for a 50-foot-long extension cord wire: If a tool uses 0-5 amperes — 18-ga. wire, 5-8 amperes — 16-ga. wire, 8-12 amperes — 14-ga. wire, 12-15 amperes — 12-ga. wire and 15-20 amperes — 10-ga. wire. For a 100-foot-long cord, the gauges should be two sizes bigger (i.e., 14 instead of 16).

For outdoor use, you must use an extension cord with a built-in GFCI (ground fault circuit interrupter) unless you have it plugged into a GFCI outlet. Outdoor electrical outlets and ones in moist areas should already be on GFCI circuits. Even though a tool seems to be operating fine, a slight short can be enough to stop your heart if the current passes through the wrong nerve.

Always remember to unplug an extension cord from the wall when you are done using it. Dogs and children seem to enjoy chewing on electric cords of all types.

Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit

Last Updated on Thursday, 03 March 2011 03:17